flushing default router list upon inet6 route flush

Hello,

When IPv6 SLAAC is configured for an interface, the kernel will update
its default router list upon receipt of a router advertisement.  In so
doing it may install a default route; in the kernel this happens in
defrouter_addreq().

If one uses "route flush" or "service routing restart" to reset the
routing tables, the default router list is not purged, so a subsequent
RA from the original default router does not update the list, and so
does not re-create the default route, even if one re-runs rtsol(8).

This appears to be a bug, but I'm not sure where best to fix it.  Should
"service routing restart" invoke "ndp -R" to flush the default router
list?  Should route(8) handle this as part of a flush command?  Or
something else?